Continuity mistake: Just as Sayid walks out of the building (number on both doors is 815), the white van pulls up. When Sayid gets in, in the exterior shot, the door he opens is opened to Sayid's left, but in the next interior shot, the door is opened to Sayid's right (the door to his left is closed). In this shot the building is seen behind Sayid - note the number 815 on both doors have vanished, and the chipped wall paint differs.
Continuity mistake: When Shannon is looking for Boone but instead finds his "jungle pal" Locke, he is gutting his dinner and gets blood on his face. The blood on Locke's face repeatedly changes, such as in one shot there's a small clot of blood beside his eye, and in another shot the blood is lower and larger.
Continuity mistake: On the beach, when Shannon questions Boone about his and Locke's whereabouts everyday, Boone wears a sleeveless tee shirt with large Asian characters on the front. Then, when Boone kneels beside Shannon the entire design actually disappears.
Continuity mistake: When Kate leans over the unconscious marshal he wakes and chokes her, and when Jack subdues him the marshal's large head bandage falls off. When Jack squeezes water into the marshal's mouth, the bandages are wrapped perfectly round his head, yet when Kate stands up the bandages are off again.
Continuity mistake: When Claire is holding Aaron talking to Locke, she says "I can't believe he is still sleeping" and they show him sleeping. She then asks Locke if he wants to hold him and then hands Aaron to Locke. His eyes are wide open. Then you see Locke obviously holding a doll in the next shot and they are talking about him still being asleep. Locke then hands Aaron to Charlie and the eyes are again wide open and they are still talking about him being asleep.
Continuity mistake: In Episode 2-23 Live Together, Die Alone When Mr Eko runs out of the hatch when John and Desmond are faking a lock down, you see Eko put his club in his belt right in the front of his pants. In the next scene as he passes out of the door the club is gone and then when he runs back to the door as it is closing he is holding it in his hand as he drops it and it falls under the door.
Continuity mistake: When Jack drops to his knees, after removing the undershirt, one white shirt lies stretched out horizontally on the ground directly in front of him, with both knees centered in front of it; the other shirt is off to his right (viewer's left), with the undershirt he drops. Three shots later, still on his knees, all three shirts lie rumpled to his right; eleven shots later, the single white shirt once again lies horizontally directly in front of him, in the very same position as the earlier shot.
Continuity mistake: Some passenger seats from the wreckage, that are seen in various shots on the island here and in other episodes, are not the same seats shown in the interior shots of the plane. There are three distinct colors/styles of passenger seating in the interior shots, blue stripe in economy, grey stripe in business class, and also greyish leather in first class, which didn't end up on the beach anyway.
Revealing mistake: When Kate pulls Ray from the burning pickup, he has bloody bruises at the center and right side of his forehead. As she drags him across the grass, in the shot when she grunts, the bruises on his forehead are at the center and left side of his forehead. This shot is flipped.
Continuity mistake: In this episode Jack works on an old crippled man to try and perform another "miracle." Remember, this is supposed to be in Jack's past. When he's looking at the x-rays in the beginning, take a look at the dates on them. They're November 16, 2005. In the last episode of season 2, Desmond says that the plane crashed in September 2004.